Process for the manufacture of mineral cattle food

ABSTRACT

Production of mineral cattle food consisting of sodium, magnesium and calcium phosphates, wherein phosphoric acid, dolomite and sodium hydroxide solution are introduced into a long extended reaction zone, conveyed therethrough with constant agitation and reacted therein, and the resulting reaction product is dried.

United States Patent Inventors Priority Joseph Cremer Hermulheim nearCologne;

Heinz l-larnisch, Lovenich; Friedrich Schulte, Hurth near Cologne;Arnuli Hinz, Knapsack near Cologne, all of Germany 888,91 1

Dec. 29, 1969 Nov. 16, 1971 Knapsack Aktiengesellschaft Knapsack,Germany Dec. 27, 1968 Germany PROCESS FOR THE MANUFACTURE OF MINERALCATTLE FOOD 15 Claims, No Drawings US. Cl 99/21, 71/646, 71/41, 23/109Int. Cl A23k 1/00,

Field of Search C05b 11/00, C01b 25/32 71/41, 64 R, 62, 64 G; 99/2, 21,23/108, 109

References Cited UNITED STATES PATENTS 5/1969 Muller 9/1969 Nielsson5/1938 Lawrence... 11/1935 Skinner 11/1938 Maclntire... 9/1942Emery..... 8/1949 McHan FOREIGN PATENTS 4/1940 Great Britian PrimaryExaminer-Norman Yudkoff Assistant Examiner-Hiram H. BernsteinAttorney-Connolly and Hutz ABSTRACT: Production of mineral cattle foodconsisting of sodium, magnesium and calcium phosphates, whereinphosphoric acid, dolomite and sodium hydroxide solution are introducedinto a long extended reaction zone, conveyed therethrough with constantagitation and reacted therein, and the resulting reaction product isdried.

PROCESS FOR THE MANUFACTURE OF MINERAL CATTLE FOOD The phosphoric acidand the dolomite are introduced into the head portion of a reactionzone, the dolomite being used in the form of particles with a size ofless than 0.1 mm., and the phosphoric acid being used in a concentrationof between and 50 weight percent; sodium hydroxide solution is added tothe reaction mixture near a point in the reaction zone which the mixturehas reached after a period of time of between 0.5 and 3.0 minutes; theresulting friable mixture is treated to comminute agglomerated matterwith a particle size of more than 3 mm.', the comminuted matter isallowed to ripen, with constant agitation, during a period of time ofbetween 1 and 10 minutes, at temperatures between 60 and 120 C., and arelative atmospheric moisture of more than 60 percent; and the resultingmaterial is dried and freed from fines having a size of less than 100microns, except for a maximum proportion of 35 weight percent, and thefines are recycled to material in the reaction zone, ahead of theripening zone therein.

The present invention relates to a process for the manufacture ofstorable cattle food consisting of sodium magnesium and calciumphosphates, wherein phosphoric acid, dolomite and sodium hydroxidesolution are introduced into a long extended reaction zone, conveyedtherethrough with constant agitation, and reacted therein, and theresulting reaction product is dried.

The reaction products so made are dried and obtained then in the form ofgranules, or ground and dried, and obtained then in powder form. As timegoes on during the storage of these mixed phosphates, it is found thatthey often coalesce more or less strongly to agglomerates. As a result,product handling and processibility are considerably handicapped or evenrendered impossible. These caking phenomena are encountered regardlessof whether the products are stored in bags or silos.

It has now unexpectedly been found that cattle food having a goodstorage life can be produced by the process of the present inventionwhich comprises introducing phosphoric acid and dolomite into the headportion of a reaction zone, the dolomite being used in the form ofparticles with a size of less than 0.1 mm. preferably less than 0.04mm., and the phosphoric acid being used in a concentration of between 10and 50 weight percent, preferably and weight percent. Following this,sodium hydroxide solution is added near a point in the reaction zonewhich the above mixture has reached after a period of between 0.5 and3.0 minutes, preferably 0.5 and 1.5 minutes. The resulting slightlyfriable mass having agglomerated matter therein is treated to comminuteagglomerates having a size large than 3 mm. and the comminuted materialis allowed to ripen, with constant agitation, during a period of betweeni and 10 minutes, preferably 1 and 5 minutes, at temperatures between 60and 120 C., preferably 90 and 120 C., and a relative atmosphericmoisture of more than 60 percent, preferably more than 90 percent.

The product so made is dried and freed then from fines having a size ofless than 100 microns, preferably less than 40 microns, except for amaximum proportion of 35 weight percent, preferably less than 10 weightpercent, and the fines are recycled to material in the reaction zone, ata place ahead of the ripening zone therein.

Only by the combination of all of the steps described hereinabove is itpossible to successfully carry out the process of the present invention.Any failure to comply with all of these steps will be found to affectthe flow properties of the final product, already after storage for someshort period of time.

The process of the present invention can be carried out with the use ofcalcined dolomite, which preferably is gently calcined dolomite.

The feed materials should conveniently be used in a quantitative ratiosuch that a 1 percent aqueous solution or suspension of the finalproduct have a pH-value of between 5 and 8, preferably 5 and 7.

The sodium hydroxide solution should preferably be used in aconcentration of substantially 50 weight percent and should beintroduced in finely divided form into the reaction zone.

The reaction product is easy to comminute prior to ripening it by theselection of a suitable flow velocity or by the selection of a suitablemixing device.

In the case of reactions, which practically are topochemical reactions,the final products tendency to later cake together has been found to bechiefly occasioned by an incomplete neutralization of the feedmaterials, coupled with an inconsistent degree of saturation of thewater of crystallization con tained in the individual phosphateparticles. During storage, especially under pressure, diffusionphenomena are noted to occur in cases like this, whereby the equilibriumis definitely established, possibly with further crystallization of theproducts to agglomerates. The tendency to cake together has also beenfound to be quite considerably influenced by the presence of relativelysmall proportions of finest particles, which cause the loose individualparticles to become closely packed, naturally with the resultantformation of a maximum contact or reaction area.

EXAMPLE la parts by weight of gently calcined dolomite (substantially 52weight percent CaO and substantially 38 weight percent MgO), 375 partsby weight phosphoric acid (50 weight percent P 0 and between about 600and 700 parts by weight H O were supplied per unit of time (limit ofvariation: l0 weight percent) near one of the end points of apaddle-type screw conveyor. The fine particulate dolomite of which l00percent consisted of particles with a size smaller than 40 microns, theexcess of phosphoric acid and the quantity of water supplied were foundto effect rapid and complete reaction between the dolomite andphosphoric acid, termed herein first neutralization stage. After asojourn time of 1.5 minutes, during which the reaction mixture travelledthrough the screw conveyor, there were added parts by weight finelydivided sodium hydroxide solution of substantially 50 weight percentstrength, approximately near the center portion of the paddletype screwconveyor, which was substantially 6 meters long. The now clotty orcoarsely friable reaction mixture was allowed to ripen for substantially6 minutes at about 70 C. and 90 percent relative atmospheric moisture.Following this, the reaction mixture was ground and dried and theNa-Ca-M g phosphate mixture was treated in an air separator so as toestablish a maximum of 10 weight percent fines with a size of less than40 microns therein. The remaining fines were recycled to the paddle-typescrew conveyor and introduced thereinto, ahead of the ripening zonetherein. The final product, stored over a period of l4 days in bags andsilos, was free from hardening phenomena and possessed free-flow properties.

To determine its hardening behavior, the product was stored over 14 daysin a warehouse in bituminized 50 kg. paper bags (10 bags superposed) orin test silos (600 X3,000 mm.).

EXAMPLE lb The feed material and procedure were the same as thosedescribed in example la, save that the dolomite contained 60 weightpercent particles with a size of 0.l mm. Following the storage test, theproduct showed patches of slight hardening, which however were found tocompletely disappear under slight pressure. (No silo test was made inthose cases in which the storage in bags was found to be accompanied bythe occurrence of hardening phenomena.)

EXAMPLE lc The feed material and procedure were the same as thosedescribed in Example In save that the sodium hydroxide solution wasadded immediately after the introduction of the dolomite and phosphoricacid into the paddle-type screw conveyor. in other words, practically noor only very little time was allowed for material to remain in the firstneutralization stage. Following the storage test, the reaction productwas found to have hardened. The bag-stored product disintegated intorelatively small fragments, on handling it.

EXAMPLE 1d The feed material and procedure were the same as thosedescribed in example 1a, save that the final product contained more than30 percent particles with a size of less than 40 microns. Following thestorage test, the bag-stored material was found to have hardened at arate increasing from the uppermost to the lowermost bags. Merelyfragments could be broken off by hand, i.e., near the upper peripheralportion of the bags. This was the best result obtained.

EXAMPLE 2a The feed material and procedure were the same as thosedescribed in example 1a save that the rotation speed of the paddle screwdrier was doubled. Following the addition of sodium hydroxide solution,the reaction product was found to first transform into a fine friablemass and later into a mass consisting of fine spheroidal particles, nearthe end of the paddle screw drier. The product was cooled and passedthrough a sieve to isolate particulate matter with a size of between 0.5and 2.5 mm. The granules was practically free from particle fractionswith a size of less than 100 microns. The material was stored in bagsand silos. The occurrence of caking phenomena was not observed and theproduct was found to possess free-flow properties.

EXAMPLE 2b The feed material and procedure were the same as thosedescribed in example 2a save that the dolomite contained 40 percentparticles with a size of 0.1 mm. and that the reaction product wasdried, immediately after introduction of the feed material. The reactionproduct so obtained was stored and found to cake together. Theagglomerates could be crushed by hand.

EXAMPLE 2c The feed material and procedure were the same as thosedescribed in example 2a, save that the final product, which consisted ofloosely packed particles, contained more than 25 percent dust fines witha size of less than 60 microns. Following the storage test, the productwas found to contain hardened material, predominantly near places withrelatively large proportions of accumulated fines therein. The hardenedmaterial was found to disintegrated under mechanical stress.

We claim:

1. A process for the manufacture of cattle food consisting of sodium,magnesium and calcium phosphates, wherein phosphoric acid, dolomite andsodium hydroxide solution are introduced into a long extended reactionzone, conveyed therethrough with constant agitation and reacted therein,and the resulting reaction product is dried, which comprises the stepsof:

a. introducing the phosphoric acid and the dolomite into the headportion of a reaction zone, the dolomite being used in the form ofparticles with a size of less than 0.1 mm., and the phosphoric acidbeing used in a concentration of between and 50 weight percent;

b. adding sodium hydroxide solution to the step (a) reaction mixturenear a point in the reaction zone which the mixture has reached after aperiod of time of between 0.5 and 3.0 minutes;

c. treating the resulting friable mass having agglomerated mattertherein to comminute agglomerates with a particle size of more than 3mm. and allowing the comminuted matter to ripen, with constantagitation, during a period of time of between 1 and 10 minutes, attemperatures between 60 and 120 C., and a relative atmospheric moistureof more than 60 percent; and

d. drying the resulting material and freeing it from fines having a sizeof less than 100 microns, except for a maximum proportion of 35 weightpercent, and recycling the fines to material in the reaction zone, at aplace ahead of the ripening zone therein.

2. The process as claimed in claim 1, wherein the dolomite is calcineddolomite and preferably is gently calcined dolomite.

3. The process as claimed in claim 1, wherein the feed materials areused in a quantitative ratio such that a 1 percent aqueous solution orsuspension of the final product has pH- value of between 5 and 8.

4. The process as claimed in claim 1, wherein the sodium hydroxidesolution is used in a concentration of about 50 weight percent.

5. The process as claimed in claim 1, wherein finely divided sodiumhydroxide solution is introduced into the reaction zone.

6. The process as claimed in claim 1, wherein the reaction product iscomminuted, prior to ripening it, by the selection of a suitable flowvelocity or by the use of a suitable mixing device.

7. The process as claimed in claim 1, wherein the dolomite has aparticle size of less than 0.04 mm.

8. The process as claimed in claim 1, wherein the phosphoric acid isused in a concentration of between 15 and 25 weight percent.

9. The process as claimed in claim 1, wherein the sodium hydroxidesolution is added near a point in the reaction zone which the reactionmixture has reached after a period of time of between 0.5 and 1.5minutes.

10. The process as claimed in claim 1, wherein the comminuted materialis allowed to ripen for a period of time of betweenl and 5 minutes.

11. The process as claimed in claim 1, wherein the comminuted materialis allowed to ripen at temperatures of between and 120 C.

12. The process as claimed in claim 1, wherein the comminuted materialis allowed to ripen at a relative atmospheric moisture of more than 90percent.

13. The process as claimed in claim 1, wherein the dried product isfreed from all particles having a size smaller than 40 microns.

14. The process as claimed in claim 1, wherein the dried product isfreed from all particles having a size smaller than microns, except fora maximum proportion of less than 10 weight percent.

15. The process as claimed in claim 1, wherein the feed materials areused in a quantitative ratio such that a 1 percent aqueous solution orsuspension of the final product has a pH- value of between 5 and 7.

2. The process as claimed in claim 1, wherein the dolomite is calcined dolomite and preferably is gently calcined dolomite.
 3. The process as claimed in claim 1, wherein the feed materials are used in a quantitative ratio such that a 1 percent aqueous solution or suspension of the final product has pH-value of between 5 and
 8. 4. The process as claimed in claim 1, wherein the sodium hydroxide solution is used in a concentration of about 50 weight percent.
 5. The process as claimed in claim 1, wherein finely divided sodium hydroxide solution is introduced into the reaction zone.
 6. The process as claimed in claim 1, wherein the reaction product is comminuted, prior to ripening it, by the selection of a suitable flow velocity or by the use of a suitable mixing device.
 7. The process as claimed in claim 1, wherein the dolomite has a particle size of less than 0.04 mm.
 8. The process as claimed in claim 1, wherein the phosphoric acid is used in a concentration of between 15 and 25 weight percent.
 9. The process as claimed in claim 1, wherein the sodium hydroxide solution is added near a point in the reaction zone which the reaction mixture has reached after a period of time of between 0.5 and 1.5 minutes.
 10. The process as claimed in claim 1, wherein the comminuted material is allowed to ripen for a period of time of between 1 and 5 minutes.
 11. The process as claimed in claim 1, wherein the comminuted material is allowed to ripen at temperatures of between 90* and 120* C.
 12. The process as claimed in claim 1, wherein the comminuted material is allowed to ripen at a relative atmospheric moisture of more than 90 percent.
 13. The process as claimed in claim 1, wherein the dried product is freed from all particles having a size smaller than 40 microns.
 14. The process as claimed in claim 1, wherein the dried product is freed from all particles having a size smaller than 100 microns, except for a maximum proportion of less than 10 weight percent.
 15. The process as claimed in claim 1, wherein the feed materials are used in a quantitative ratio such that a 1 percent aqueous solution oR suspension of the final product has a pH-value of between 5 and
 7. 